Aluminum-Clad Wood Windows
real timber inside, weather armor outside
An aluminum-clad wood window is a wood window whose exterior faces are covered by an extruded aluminum shell: the wood does the structural and thermal work, the aluminum takes the weather and carries the exterior color. The four clad systems on this page - Clad Flush, Clad Hidden Sash, Clad Passive and Timber Lift & Slide - are made to order in Poland for US DDP or Canadian DAP delivery to the agreed site. I coordinate the drawings, the order and the shipment, and price them from your drawings.
What is a clad window (and what it is not)?
The cladding is an extruded aluminum shell clipped to the outside of the frame and the sash on clips. It is not glued to the wood. Between the shell and the timber there is a ventilated gap that helps moisture escape. Drainage and installation details still matter. From the street you see aluminum. From the room you see solid laminated wood - a three-layer scantling on the concealed-sash line - with a stain or lacquer on it.
Two things it is not. It is not an aluminum window with a wood veneer on the inside: the frame and sash are wood through and through, and the aluminum is a cover, not the structure. And it is not a PVC-wrapped window: the exterior is a powder-coated metal extrusion, not a plastic sleeve. The concealed-sash version, Clad Hidden Sash, is the timber counterpart of the aluminum systems on my hidden sash windows page.
You will see this build sold under several names: clad windows, aluminum clad windows, alu clad windows, metal clad windows, wood clad windows, aluclad. They describe the same thing - timber frame and sash with an aluminum shell outside. The one detail worth checking on any quote is what the shell is made of; on the systems on this page it is an aluminum extrusion.
| Element | Material | Job |
|---|---|---|
| Structure | Laminated wood | Carries the glass, the hardware and the loads |
| Thermal performance | Wood core plus the glazing unit | Insulates; the shell sits outside the thermal line |
| Weather face | Extruded aluminum shell | Takes rain, UV and temperature swings |
| Exterior color | Powder-coated aluminum | Any RAL, matte or textured, or a wood-grain decor |
| Interior finish | Stain or lacquer on wood | Transparent stain or opaque color, chosen separately |
Why clad wood makes sense for projects in the US and Canada
The main reasons are the timber interior and reduced exposure of the exterior wood. Import charges are a separate, project-specific check: I confirm the product classification and applicable charges with the customs broker before finalizing a DDP quote. Cladding alone does not establish the customs treatment or a cost saving.
Expect clad to price above a comparable full-aluminum window. It is two builds in one: profiled and selected timber, four coats of lacquer with machine and hand sanding, clips for the shell, fitted aluminum covers with silicone sealing, and the glazing unit glued in on tape - and softer timber means more rework than metal. What you get for it is a timber interior and, on the better lines, a stronger thermal result.
There is also the maintenance schedule. Exposed exterior timber needs its finish renewed periodically; an aluminum shell reduces that work, while still needing cleaning and coating checks. Then there is the room itself: an oak or pine interior reads warmer than a metal frame, and on a custom home that is usually why the client asked for wood in the first place. The cladding lets them keep the interior they wanted with less exposed timber to maintain outside. The longer version of that trade-off is in aluclad vs aluminum vs wood windows.
The four clad systems I quote
All four are built in Poland by the same timber window maker as the unclad wood lines, and all four sit in the aluclad category. The selection question is what the exterior should look like: flush and flat, sash concealed, deeper profiles for low-energy design, or a sliding wall of glass.
Flush exterior
Clad Flush
- Frame and sash sit flush on the outside - one flat plane, no stepped sash
- Standard, XL and MAX variants; 3 sealing lines; pine, meranti or oak
- Interior transparent or opaque RAL; exterior any RAL or a wood-grain decor on the aluminum
Concealed sash
Clad Hidden Sash
- Opening sash sits behind the frame from outside, so fixed and operable units read the same
- 3.21 in (81.5 mm) standard depth or 3.60 in (91.5 mm) XL; XL glazing up to 2.28 in (58 mm)
- Concealed hinges for sash loads up to 331 lb (150 kg); published Rw up to 48 dB, with glass and configuration confirmed separately
Insulated frame
Clad Passive
- Published overall depth 4.86 in (123.5 mm), with an insulating foam layer between timber and aluminum
- Supplier describes the system as Passivhaus Institut certified; the applicable certificate and assembly must be checked for your project
- Triple glazing and a warm-edge spacer; confirm the glass build-up against the selected profile
Illustrative manufacturer interior - not a Windows Guy project.
Patio door
Timber Lift & Slide
- Published frame depth 9.45 in (240 mm); narrow-frame option up to about 11 ft 10 in (3,600 mm) sash height and 661 lb (300 kg)
- Moving panel(s) plus expansive fixed glazing, in timber or aluminum-clad timber
- Fixed glazing and the moving-door threshold are detailed separately for each opening
| System | Frame depth | Sealing lines | Glazing | Published U-factor / converted Uw | Notes |
|---|---|---|---|---|---|
| Clad Flush | 3.54 in. (90 mm) - selected section to be confirmed | 3 sealing lines | Double or triple pane | Approx. 0.19-0.21 Btu/(h ft2 F); not an NFRC rating | Flush exterior |
| Clad Hidden Sash | 3.21 in. / 3.60 in. (81.5 / 91.5 mm) | 3 sealing lines | Double or triple pane; XL glass up to 2.28 in. (58 mm) | From 0.16 Btu/(h ft2 F) | Concealed sash; Rw up to 48 dB; security options depend on configuration |
| Clad Passive | 4.86 in. (123.5 mm) | 3 gaskets; enlarged main seal and additional central seal | Triple pane with Swisspacer Ultimate warm-edge spacer | From approx. 0.11 Btu/(h ft2 F); not an NFRC rating | Additional frame insulation; supplier PHI claim requires certificate review |
| Timber Lift & Slide | 9.45 in. (240 mm) - US catalogue configuration | Confirm selected section | Large-format triple glazing supported | From 0.20 Btu/(h ft2 F) | Wood or clad wood; narrow-frame and hardware limits differ |
U-factors are in Btu/(h.ft2.F). Values marked converted are approximate conversions of European Uw, not NFRC ratings. US catalog values are configuration-dependent; I verify the applicable test documentation for the quoted assembly. Rw is a European acoustic rating, not STC. Security ratings require the specified glazing and hardware. The supplier publishes a Passivhaus Institut certification claim. I request the exact certificate and applicable configuration for a project; project compliance is assessed per size, glass and install; see passive house windows.
Real units, from the factory floor to the room
Renderings explain a section; photographs show the scale. Three clad units in production, photographed from the timber side, and a finished home with the concealed-sash line.
Nailing fin - Clad Hidden Sash
A wide fixed unit with a nailing fin fitted along the frame for a North American wood-frame opening, photographed in production before packing. Clad Hidden Sash
12 ft+ - Timber Lift & Slide
A lift-and-slide frame more than 12 ft (3.7 m) tall in final assembly. Panel size is confirmed against glass weight and hardware. Timber Lift & Slide
Double doors - Clad Flush
Double doors with transoms, timber side before finishing. The same line is built as French doors or a single door. Clad Flush
Installed - Clad Hidden Sash
Floor-to-ceiling divided-lite glazing and a French door, interior timber in an opaque color. Manufacturer reference installation - not a Windows Guy project. Clad Hidden Sash
Aluminum-clad vs vinyl-clad vs full aluminum vs bare wood
Four constructions with different exterior materials and maintenance needs. Full thermally broken aluminum is the right call when the opening is very large or the sightlines have to be as slim as possible - how the thermal break works. Bare wood is for projects where the exposed timber exterior is the point and the finish schedule is accepted. Different, not worse. The shell-by-shell detail, including dark colors and US dealer coverage, is in vinyl-clad vs aluminum-clad wood windows.
| Attribute | Aluminum-clad wood | Vinyl (PVC)-clad wood | Full aluminum | Bare wood |
|---|---|---|---|---|
| Exterior material | Powder-coated extruded aluminum shell, clipped on over a vented gap | PVC cladding over a wood frame | Thermally broken aluminum profile | Lacquered timber |
| Interior material | Solid laminated wood | Wood | Aluminum | Solid laminated wood |
| Exterior maintenance | Wash, check drainage slots, inspect the coating | Wash and inspect the coating | Wash and inspect the coating | Periodic finish renewal |
| Interior feel | Warm timber | Wood | Metal, slim | Warm timber |
| Thermal behaviour of the frame | Wood core insulates; the shell is outside the thermal line | Wood core insulates | Depends on the thermal break; conducts more than a wood frame | Wood insulates |
| Exterior color options | Any RAL powder coat, matte or textured, wood-grain decor | The maker's palette | Any RAL powder coat | Any stain or opaque color |
| Where I recommend it | Custom homes that want timber inside and a colored, low-upkeep exterior | Where local service, availability and budget lead the decision | The largest spans and the slimmest sightlines | Traditional homes and renovations where the exposed timber is the point |
Colors: two finishes, chosen separately
The aluminum shell and the wood interior are finished independently. Outside: any RAL powder coat, matte or textured, or a wood-grain decor on the aluminum. Inside: a transparent stain that shows the grain, or an opaque RAL or NCS color, over a water-based hybrid lacquer.
The usual custom-home pick is a dark exterior - anthracite or black - with natural oak inside, and the order form treats those as two separate lines. Browse the RAL palette and read how European window colors and finishes work.
Outside: aluminum
Inside: timber
Maintenance: what the cladding removes and what stays
Exterior
Wash the aluminum with water and a mild detergent and keep the drainage slots at the bottom of the frame clear. Inspect the coating, joints and seals too, and follow the system care instructions for damage or exposed locations.
Interior
Keep standing water off the timber and inspect the finish. Clean and repair it with products compatible with the supplied coating, following its care instructions.
Hardware
Inspect operation and follow the hardware maker's lubrication and adjustment instructions. Have heavy or misaligned sashes checked by a qualified installer.
Sealed glazing units
Clean the glass with compatible products and inspect glazing seals. Persistent moisture between panes needs a service assessment.
Species and interior finish
Pine, meranti and oak are listed for Clad Flush. Species choices vary by system, so confirm the selected timber and finish with a sample. Laminated timber construction helps control movement, but moisture conditions and maintenance still matter.
Choose a transparent finish that shows the grain or an opaque interior color. Confirm the coating system for your order. The species table, the unclad lines and how the finishes age are on the wood windows page.
How an order runs
Five steps, one point of contact: you prepare the openings and receive the truck.
- 1
Send the drawings
Window schedule or elevations, whatever you have. I mark up what still needs a decision: opening types, sizes, glass, exterior RAL, interior finish.
- 2
Quote and shop drawings
You get a US DDP or Canadian DAP estimate with its scope stated first. Once the system and both finishes are fixed, shop drawings come back for approval before anything is cut.
- 3
Production in Poland
The frames are laminated, machined, clad, glazed and finished at the factory. I check the order confirmation against the approved drawings line by line.
- 4
Container and customs, by destination
The units are crated and shipped by container. US DDP includes the agreed duty and clearance. For Canada DAP, the Canadian buyer is importer of record and their broker clears the goods on their behalf.
- 5
Delivery
Trucked to your site. Production and delivery timing is confirmed for your system, finish and order before approval.
The full import sequence is in the DDP import guide, and the stage-by-stage timing in European window lead times.
Building in Canada? Orders there ship DAP to the site, duty-free under CETA with an origin declaration I prepare - the Canadian path is on European windows for Canadian projects.
Aluminum-clad windows - common questions
What is a clad window?+
A clad window is a wood window whose exterior faces are covered by an extruded aluminum shell. The shell is clipped to the outside of the frame and sash over a ventilated gap; the wood carries the structure and the insulation, the aluminum takes the weather and the exterior color. From inside the room it is a solid laminated wood window.
Can you paint aluminum-clad windows?+
Aluminum-clad windows get their exterior color at the factory, so choose it when ordering: any RAL powder coat, matte or textured, or a wood-grain decor, depending on the selected cladding. If the coating later needs repair or repainting, follow the coating supplier's preparation and repair guidance. The interior timber finish is separate and needs compatible maintenance products.
Are aluminum clad windows the same as wood clad windows?+
In practice, yes. Clad windows, aluminum clad windows, alu clad windows, metal clad windows, wood clad windows and aluclad windows all point to the same build: a wood frame and sash with a cladding shell on the exterior. When a seller says only "wood clad", ask what the shell is made of. On the systems I quote it is an aluminum extrusion with a powder coat or wood-grain decor.
Which clad windows do you supply for projects in the US and Canada?+
Four clad systems: Clad Flush, Clad Hidden Sash, Clad Passive and Timber Lift & Slide. Each is quoted from your drawings with the exterior RAL and the interior timber finish chosen separately. Pricing is per project and lead time is confirmed per order.
Is aluminum-clad better than vinyl-clad wood?+
Aluminum-clad and vinyl-clad wood windows differ in the shell, not the wood. Aluminum cladding is a powder-coated metal extrusion clipped on over a vented gap, in any RAL color with crisp edges; vinyl cladding is a formed PVC cover in the maker's palette, with a wider US dealer network. Aluminum suits colored, modern exteriors; vinyl suits projects led by budget and local service.
How long does the aluminum cladding last?+
I do not put a year count on it. Aluminum cladding reduces the timber's exposure to rain and sunlight. A ventilated space behind the cover helps moisture escape, but drainage, seals, coatings and installation still need inspection and care. Exposure and maintenance affect the service life of the complete window.
How are import charges confirmed?+
Import treatment depends on the product construction, origin and rules in force when it enters the US. I confirm the classification and applicable charges with the customs broker for the proposed system before finalizing a DDP quote. An aluminum exterior alone is not enough to determine the classification or promise a saving.
Can the inside be a different color from the outside?+
Yes. The exterior aluminum and interior timber finishes are chosen separately. Compare a RAL exterior color with a transparent timber finish or an opaque interior color, using samples for the selected species and coating. A dark exterior with natural oak inside is one possible combination.
Compare the clad construction before specifying
Use the house-line selection sheet to compare the interior timber, exterior shell and opening roles. Confirm the chosen section, glazing and applicable assembly documents against your drawings.
Speccing clad wood
for your next build?
Send me the drawings or the window schedule and I'll come back with a US DDP or Canadian DAP estimate for the clad system that fits the elevation. Browse the timber reference cards in Studio, or just get in touch.